Norwich Roofers handles chimney stack rebuilds for homeowners in Swaffham, and this page walks you through exactly what happens from the moment we arrive to the moment we leave.
Call any time. Calls are answered day and night and passed straight to our roofers.
The first step is always a proper look at the chimney, not a glance from the garden or a guess based on the age of the house. For a rebuild, that means getting up to roof level to assess the stack face to face. Binoculars can flag that something is wrong, but they cannot tell you how many courses need to come down, what the mortar is like behind the joints, or whether the flashing needs replacing as part of the same job.
During the assessment we check the condition of the bricks and mortar joints from the top of the stack down to the roofline, the state of the flaunching and chimney pot, and the lead (or other) flashing at the base. We also note the brick type, colour and bonding pattern so we can source a match before the scaffold goes up. Identifying the right brick at this stage avoids delays mid-job.
If there is any sign of nesting in the flue, we note that for the homeowner, because a blocked or debris-filled flue needs clearing separately before the chimney can be used safely. Nest removal at height is something to arrange before the rebuild, not after.
All chimney rebuild work is carried out from a properly erected scaffold platform. This is not a choice we make for convenience - it is the only way to do the job safely and to the standard the work requires. A roofer working off a roof ladder cannot remove and rebuild multiple courses of brickwork with the control and care needed to do it properly.
For a standard house in Swaffham, the scaffold is usually a tower or bridging structure erected against the relevant elevation, with a platform at eaves level or just above it, and a working platform at stack level. It is tied to the building where needed and boarded out properly.
Homeowners should expect some disruption to parking if the scaffold sits over a driveway or on the pavement, and access to that elevation of the house may be restricted while the platform is up. We let you know the access arrangements before we start. The scaffold usually stays up for the duration of the rebuild and is struck once the mortar has had adequate time to set.
Once the platform is in place, the chimney pot is lifted off and set aside if it is to be reused, or replaced if it is cracked or broken. The flaunching - the mortar collar around the base of the pot - is broken out. This is almost always replaced rather than repaired, because a partial repair to old flaunching does not last.
Bricks are then removed course by course from the top down. We work carefully to avoid dropping material onto the roof covering below - the platform is positioned to catch debris, and the area below the scaffold is kept clear. Bricks that are still in good condition are set to one side and will be reused in the rebuild where they match well. Damaged, spalled or heavily contaminated bricks go for disposal.
We take the stack down to the first course of fully sound, undamaged brickwork. This is the point from which the rebuild starts. In some cases that is two or three courses below the top; on a badly deteriorated stack it may be eight to ten courses or more, right back to the roofline. The assessment beforehand gives a good indication of how far down we are likely to go, though the actual condition is only fully confirmed once the work is under way.
The new courses go up using a mortar mix suited to the brick type and the age of the building. On older properties, lime or natural hydraulic lime mortar is the correct choice. On more modern builds with harder bricks, a sand and cement mix is appropriate. Using the wrong mortar type is a common cause of premature failure, so this is not a detail to overlook.
Bricks are laid in the same bond as the original stack to maintain the pattern and structural integrity. Where new bricks are going in alongside reused originals, we work to keep the colour and texture blend as close as possible. The mortar joint width and finish (usually a weatherstruck or slightly recessed joint on chimneys) is matched to the existing work below the rebuild section.
Stacks with string courses, corbelling or decorative features need to be replicated, which takes longer and requires more care.
While the stack is exposed on scaffold, we inspect the lead flashing at the base. This is where the stack meets the roof slope and it is a very common point of water entry. If the lead has lifted, cracked or been previously repaired with flash band tape, it should be addressed now - the scaffold is already up, and the cost of leaving failed flashing in place is a repeat leak and potentially more internal damage.
Stepped flashing on the sides, the apron at the front of the stack and the back gutter behind it are all checked. Code 4 lead (1.8 mm) is the standard material. Where sections need replacing, new lead is cut, dressed and pointed into the mortar joints in the correct way.
Once the top course of the new stack is done and the mortar has begun to go off, the flaunching is laid. This is a mortar fillet applied around the base of the chimney pot, sloped outward so that rain runs off it rather than sitting against the base of the pot. It is worked up to the pot and consolidated around it to hold it firmly in place.
The chimney pot is then reset (or a new pot fitted if the original was damaged). On stacks where the pot is being capped or a cowl fitted, this goes on at the same stage. A ventilated cap on an unused flue, or an anti-downdraught cowl on a working chimney, is straightforward to fit while the scaffold is still standing.
Once mortar has cured to the point where it is no longer vulnerable to smearing, any excess is cleaned from the brick faces. Mortar smears on brickwork look untidy and can be hard to remove once fully hardened, so this is done while the material is still in a workable state.
Debris from the taken-down courses - broken brick, old mortar, pieces of old flaunching - is cleared from the scaffold platform, bagged and removed from site. Roofing felt, tiles or slates around the base of the stack are checked and re-seated if they have been disturbed during the work.
The scaffold is struck once the mortar has had sufficient time to set properly, which depends on the mortar type used and the weather conditions during the cure period. Lime mortars in particular should not be allowed to dry too quickly in hot weather, and should be protected from frost while curing. We factor this into the programme when scheduling the job.
If you have a chimney that needs attention in Swaffham or a neighbouring village, call us for a roof-level assessment. We will walk you through what the job involves for your specific stack before any work is agreed.
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Call any time. Calls are answered day and night and passed straight to our roofers.
